Differential Diagnosis for Generalized Abdominal Pain

When approaching a patient with generalized abdominal pain, it's crucial to consider a broad range of potential causes. The differential diagnosis can be organized into several categories to help guide the diagnostic process.

• Single Most Likely Diagnosis

  • Gastroenteritis: This is often the most common cause of generalized abdominal pain, especially if accompanied by symptoms like diarrhea, vomiting, and fever. Justification: High prevalence, often related to viral or bacterial infections.
  • Irritable Bowel Syndrome (IBS): Although IBS typically presents with chronic symptoms, an acute exacerbation can cause generalized abdominal pain. Justification: Common condition, can have acute worsening of symptoms.

• Other Likely Diagnoses

  • Constipation: Can cause significant abdominal discomfort and is very common. Justification: Frequent cause of abdominal pain, especially in patients with altered bowel habits.
  • Urinary Tract Infection (UTI): While often localized to the lower abdomen, a UTI can cause generalized pain, especially if it involves the kidneys (pyelonephritis). Justification: Common in certain populations (e.g., women), can cause severe pain.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause generalized abdominal pain, especially if there's significant inflammation. Justification: Important to consider in patients with chronic symptoms or those with a family history.
  • Peptic Ulcer Disease: Gastric or duodenal ulcers can cause generalized abdominal pain, especially if perforation occurs. Justification: Significant cause of abdominal pain, especially in patients with risk factors like NSAID use.

• Do Not Miss Diagnoses

  • Appendicitis: Although classically presents with localized right lower quadrant pain, early or atypical presentations can cause generalized pain. Justification: Critical to diagnose early due to risk of perforation and peritonitis.
  • Ectopic Pregnancy: A life-threatening condition that can cause generalized abdominal pain in women of childbearing age. Justification: Must be considered in any female patient of childbearing age with abdominal pain.
  • Ruptured Aortic Aneurysm: Presents with severe, tearing abdominal pain and is immediately life-threatening. Justification: High mortality if not promptly diagnosed and treated.
  • Mesenteric Ischemia: Can cause severe, diffuse abdominal pain out of proportion to physical findings. Justification: High risk of bowel infarction and death if not promptly treated.

• Rare Diagnoses

  • Porphyrias: A group of disorders that can cause acute, severe abdominal pain among other symptoms. Justification: Rare, but important to consider in patients with recurrent, unexplained abdominal pain.
  • Abdominal Migraine: A condition that can cause episodic abdominal pain, often in children. Justification: Less common, but should be considered in the differential for recurrent abdominal pain without other clear causes.
  • Celiac Disease: Can cause chronic abdominal pain and malabsorption. Justification: Important to consider in patients with chronic symptoms and signs of malabsorption.

Physical Exam to Help Rule In or Out Each Diagnosis

• Inspection: Look for signs of distress, abdominal distension, or masses.
• Auscultation: Listen for bowel sounds (absence may indicate ileus, presence may indicate obstruction).
• Percussion: Check for tenderness, guarding, or rebound tenderness (suggestive of peritonitis).
• Palpation: Assess for tenderness, masses, or organomegaly.
• Specific maneuvers:
  • McBurney's point tenderness for appendicitis.
  • Cullen's sign (bluish discoloration around the umbilicus) or Grey Turner's sign (flank bruising) for hemorrhagic pancreatitis or ruptured abdominal aortic aneurysm.
  • Psoas sign for retroperitoneal hemorrhage or abscess.
  • Rovsing's sign for appendicitis (tenderness in the right lower quadrant when palpating the left lower quadrant).

Each of these diagnoses and physical exam techniques should be considered in the context of the patient's overall clinical presentation, including history, laboratory findings, and imaging studies, to narrow down the differential diagnosis and guide further management.